On Saturday, January 30, 2016 at 2:49:27 PM UTC-7, K m wrote:
On Thursday, January 28, 2016 at 8:56:01 PM UTC-7, K m wrote:
Group,
My club is looking to convert a Twin Astir brake system to a Hydraulic Disk from a Mechanical Drum. Our serial number does not fall within the serial number range of the Kit that is offered by Lindner. We have the Lindner kit and will be going with a 337. My question is does anyone know of a 337 on an Astir brake mod? Also, I have been trying to find info on any different versions of the Astir and can't find much. Is there any reference online that points to different models or versions? Ive read that water ballast was an option and some models came with a disk brake from the factory (These have a different wheel carrier structure). Does anyone know if gross weights remained the same on the Astir through the production run? This info may hel when submitting paperwork to the FAA.
Thanks!

It was brought to my attention in a PM that my first post may have been too vague for a legitimate answer. Utah Soaring Association (USA)is retrofitting a disk brake onto a G103 Twin Astir. It was also pointed out to me that there were 7 different variants of the Astir (?!). The USA club owns two Twin II's (One an Acro) and two Astir's. I know of some factory options for the Astir (Including a trainer version) but never anything close to 7 variants. Is there reference for this somewhere?
Our Astirs have the welded steel tube wheel carriers which rotate sideways under the rear seat when they retract.
Thanks for any info.

Had a phone chat with the original poster this morning. USA owns two Twin Astir 1's with the retract. The serial numbers are 5 apart, 3285 and 3290. The G-103 production underwent some serial production changes. For example, some have a single retract handle in the front seat, others in both seats. It's not clear what changes may have been options or serial production changes. ltb-Lindner.com hopefully has serial production data and would know whether the G-103 in question was produced with a drum or disc brake. The service bulletin allows retro-fitting of a disc brake on serial numbers 3000-3139, except for the T models (fixed gear). Presumably, higher serial numbers weren't included because they were built with disc brakes installed. At least one of the above has a disc brake. If that's the case, then it would seem the disc brake installation could be made as restorative without a 337. Maybe someone qualified could chime in about that. There were some further improvements made to the original disc brake system, which would be an approved installation.

Frank Whiteley-